drivers/s390/scsi/zfcp_qdio.c - kernel/msm-4.19 - Gitiles

 /*
  * zfcp device driver
  *
  * Setup and helper functions to access QDIO.
  *
  * Copyright IBM Corporation 2002, 2009
  */

 #define KMSG_COMPONENT "zfcp"
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

 #include "zfcp_ext.h"

 #define QBUFF_PER_PAGE		(PAGE_SIZE / sizeof(struct qdio_buffer))

 static int zfcp_qdio_buffers_enqueue(struct qdio_buffer **sbal)
 {
 	int pos;

 	for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos += QBUFF_PER_PAGE) {
 		sbal[pos] = (struct qdio_buffer *) get_zeroed_page(GFP_KERNEL);
 		if (!sbal[pos])
 			return -ENOMEM;
 	}
 	for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos++)
 		if (pos % QBUFF_PER_PAGE)
 			sbal[pos] = sbal[pos - 1] + 1;
 	return 0;
 }

 static struct qdio_buffer_element *
 zfcp_qdio_sbale(struct zfcp_qdio_queue *q, int sbal_idx, int sbale_idx)
 {
 	return &q->sbal[sbal_idx]->element[sbale_idx];
 }

 /**
  * zfcp_qdio_free - free memory used by request- and resposne queue
  * @qdio: pointer to the zfcp_qdio structure
  */
 void zfcp_qdio_free(struct zfcp_qdio *qdio)
 {
 	struct qdio_buffer **sbal_req, **sbal_resp;
 	int p;

 	if (qdio->adapter->ccw_device)
 		qdio_free(qdio->adapter->ccw_device);

 	sbal_req = qdio->req_q.sbal;
 	sbal_resp = qdio->resp_q.sbal;

 	for (p = 0; p < QDIO_MAX_BUFFERS_PER_Q; p += QBUFF_PER_PAGE) {
 		free_page((unsigned long) sbal_req[p]);
 		free_page((unsigned long) sbal_resp[p]);
 	}
 }

 static void zfcp_qdio_handler_error(struct zfcp_qdio *qdio, char *id)
 {
 	struct zfcp_adapter *adapter = qdio->adapter;

 	dev_warn(&adapter->ccw_device->dev, "A QDIO problem occurred\n");

 	zfcp_erp_adapter_reopen(adapter,
 				ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED |
 				ZFCP_STATUS_COMMON_ERP_FAILED, id, NULL);
 }

 static void zfcp_qdio_zero_sbals(struct qdio_buffer *sbal[], int first, int cnt)
 {
 	int i, sbal_idx;

 	for (i = first; i < first + cnt; i++) {
 		sbal_idx = i % QDIO_MAX_BUFFERS_PER_Q;
 		memset(sbal[sbal_idx], 0, sizeof(struct qdio_buffer));
 	}
 }

 /* this needs to be called prior to updating the queue fill level */
 static void zfcp_qdio_account(struct zfcp_qdio *qdio)
 {
 	ktime_t now;
 	s64 span;
 	int free, used;

 	spin_lock(&qdio->stat_lock);
 	now = ktime_get();
 	span = ktime_us_delta(now, qdio->req_q_time);
 	free = max(0, atomic_read(&qdio->req_q.count));
 	used = QDIO_MAX_BUFFERS_PER_Q - free;
 	qdio->req_q_util += used * span;
 	qdio->req_q_time = now;
 	spin_unlock(&qdio->stat_lock);
 }

 static void zfcp_qdio_int_req(struct ccw_device *cdev, unsigned int qdio_err,
 			      int queue_no, int first, int count,
 			      unsigned long parm)
 {
 	struct zfcp_qdio *qdio = (struct zfcp_qdio *) parm;
 	struct zfcp_qdio_queue *queue = &qdio->req_q;

 	if (unlikely(qdio_err)) {
 		zfcp_dbf_hba_qdio(qdio->adapter->dbf, qdio_err, first,
 					count);
 		zfcp_qdio_handler_error(qdio, "qdireq1");
 		return;
 	}

 	/* cleanup all SBALs being program-owned now */
 	zfcp_qdio_zero_sbals(queue->sbal, first, count);

 	zfcp_qdio_account(qdio);
 	atomic_add(count, &queue->count);
 	wake_up(&qdio->req_q_wq);
 }

 static void zfcp_qdio_resp_put_back(struct zfcp_qdio *qdio, int processed)
 {
 	struct zfcp_qdio_queue *queue = &qdio->resp_q;
 	struct ccw_device *cdev = qdio->adapter->ccw_device;
 	u8 count, start = queue->first;
 	unsigned int retval;

 	count = atomic_read(&queue->count) + processed;

 	retval = do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, start, count);

 	if (unlikely(retval)) {
 		atomic_set(&queue->count, count);
 		/* FIXME: Recover this with an adapter reopen? */
 	} else {
 		queue->first += count;
 		queue->first %= QDIO_MAX_BUFFERS_PER_Q;
 		atomic_set(&queue->count, 0);
 	}
 }

 static void zfcp_qdio_int_resp(struct ccw_device *cdev, unsigned int qdio_err,
 			       int queue_no, int first, int count,
 			       unsigned long parm)
 {
 	struct zfcp_qdio *qdio = (struct zfcp_qdio *) parm;
 	int sbal_idx, sbal_no;

 	if (unlikely(qdio_err)) {
 		zfcp_dbf_hba_qdio(qdio->adapter->dbf, qdio_err, first,
 					count);
 		zfcp_qdio_handler_error(qdio, "qdires1");
 		return;
 	}

 	/*
 	 * go through all SBALs from input queue currently
 	 * returned by QDIO layer
 	 */
 	for (sbal_no = 0; sbal_no < count; sbal_no++) {
 		sbal_idx = (first + sbal_no) % QDIO_MAX_BUFFERS_PER_Q;
 		/* go through all SBALEs of SBAL */
 		zfcp_fsf_reqid_check(qdio, sbal_idx);
 	}

 	/*
 	 * put range of SBALs back to response queue
 	 * (including SBALs which have already been free before)
 	 */
 	zfcp_qdio_resp_put_back(qdio, count);
 }

 /**
  * zfcp_qdio_sbale_req - return ptr to SBALE of req_q for a struct zfcp_fsf_req
  * @qdio: pointer to struct zfcp_qdio
  * @q_rec: pointer to struct zfcp_queue_rec
  * Returns: pointer to qdio_buffer_element (SBALE) structure
  */
 struct qdio_buffer_element *zfcp_qdio_sbale_req(struct zfcp_qdio *qdio,
 						struct zfcp_queue_req *q_req)
 {
 	return zfcp_qdio_sbale(&qdio->req_q, q_req->sbal_last, 0);
 }

 /**
  * zfcp_qdio_sbale_curr - return curr SBALE on req_q for a struct zfcp_fsf_req
  * @fsf_req: pointer to struct fsf_req
  * Returns: pointer to qdio_buffer_element (SBALE) structure
  */
 struct qdio_buffer_element *zfcp_qdio_sbale_curr(struct zfcp_qdio *qdio,
 						 struct zfcp_queue_req *q_req)
 {
 	return zfcp_qdio_sbale(&qdio->req_q, q_req->sbal_last,
 			       q_req->sbale_curr);
 }

 static void zfcp_qdio_sbal_limit(struct zfcp_qdio *qdio,
 				 struct zfcp_queue_req *q_req, int max_sbals)
 {
 	int count = atomic_read(&qdio->req_q.count);
 	count = min(count, max_sbals);
 	q_req->sbal_limit = (q_req->sbal_first + count - 1)
 					% QDIO_MAX_BUFFERS_PER_Q;
 }

 static struct qdio_buffer_element *
 zfcp_qdio_sbal_chain(struct zfcp_qdio *qdio, struct zfcp_queue_req *q_req,
 		     unsigned long sbtype)
 {
 	struct qdio_buffer_element *sbale;

 	/* set last entry flag in current SBALE of current SBAL */
 	sbale = zfcp_qdio_sbale_curr(qdio, q_req);
 	sbale->flags |= SBAL_FLAGS_LAST_ENTRY;

 	/* don't exceed last allowed SBAL */
 	if (q_req->sbal_last == q_req->sbal_limit)
 		return NULL;

 	/* set chaining flag in first SBALE of current SBAL */
 	sbale = zfcp_qdio_sbale_req(qdio, q_req);
 	sbale->flags |= SBAL_FLAGS0_MORE_SBALS;

 	/* calculate index of next SBAL */
 	q_req->sbal_last++;
 	q_req->sbal_last %= QDIO_MAX_BUFFERS_PER_Q;

 	/* keep this requests number of SBALs up-to-date */
 	q_req->sbal_number++;

 	/* start at first SBALE of new SBAL */
 	q_req->sbale_curr = 0;

 	/* set storage-block type for new SBAL */
 	sbale = zfcp_qdio_sbale_curr(qdio, q_req);
 	sbale->flags |= sbtype;

 	return sbale;
 }

 static struct qdio_buffer_element *
 zfcp_qdio_sbale_next(struct zfcp_qdio *qdio, struct zfcp_queue_req *q_req,
 		     unsigned int sbtype)
 {
 	if (q_req->sbale_curr == ZFCP_LAST_SBALE_PER_SBAL)
 		return zfcp_qdio_sbal_chain(qdio, q_req, sbtype);
 	q_req->sbale_curr++;
 	return zfcp_qdio_sbale_curr(qdio, q_req);
 }

 static void zfcp_qdio_undo_sbals(struct zfcp_qdio *qdio,
 				 struct zfcp_queue_req *q_req)
 {
 	struct qdio_buffer **sbal = qdio->req_q.sbal;
 	int first = q_req->sbal_first;
 	int last = q_req->sbal_last;
 	int count = (last - first + QDIO_MAX_BUFFERS_PER_Q) %
 		QDIO_MAX_BUFFERS_PER_Q + 1;
 	zfcp_qdio_zero_sbals(sbal, first, count);
 }

 static int zfcp_qdio_fill_sbals(struct zfcp_qdio *qdio,
 				struct zfcp_queue_req *q_req,
 				unsigned int sbtype, void *start_addr,
 				unsigned int total_length)
 {
 	struct qdio_buffer_element *sbale;
 	unsigned long remaining, length;
 	void *addr;

 	/* split segment up */
 	for (addr = start_addr, remaining = total_length; remaining > 0;
 	     addr += length, remaining -= length) {
 		sbale = zfcp_qdio_sbale_next(qdio, q_req, sbtype);
 		if (!sbale) {
 			atomic_inc(&qdio->req_q_full);
 			zfcp_qdio_undo_sbals(qdio, q_req);
 			return -EINVAL;
 		}

 		/* new piece must not exceed next page boundary */
 		length = min(remaining,
 			     (PAGE_SIZE - ((unsigned long)addr &
 					   (PAGE_SIZE - 1))));
 		sbale->addr = addr;
 		sbale->length = length;
 	}
 	return 0;
 }

 /**
  * zfcp_qdio_sbals_from_sg - fill SBALs from scatter-gather list
  * @fsf_req: request to be processed
  * @sbtype: SBALE flags
  * @sg: scatter-gather list
  * @max_sbals: upper bound for number of SBALs to be used
  * Returns: number of bytes, or error (negativ)
  */
 int zfcp_qdio_sbals_from_sg(struct zfcp_qdio *qdio,
 			    struct zfcp_queue_req *q_req,
 			    unsigned long sbtype, struct scatterlist *sg,
 			    int max_sbals)
 {
 	struct qdio_buffer_element *sbale;
 	int retval, bytes = 0;

 	/* figure out last allowed SBAL */
 	zfcp_qdio_sbal_limit(qdio, q_req, max_sbals);

 	/* set storage-block type for this request */
 	sbale = zfcp_qdio_sbale_req(qdio, q_req);
 	sbale->flags |= sbtype;

 	for (; sg; sg = sg_next(sg)) {
 		retval = zfcp_qdio_fill_sbals(qdio, q_req, sbtype,
 					      sg_virt(sg), sg->length);
 		if (retval < 0)
 			return retval;
 		bytes += sg->length;
 	}

 	/* assume that no other SBALEs are to follow in the same SBAL */
 	sbale = zfcp_qdio_sbale_curr(qdio, q_req);
 	sbale->flags |= SBAL_FLAGS_LAST_ENTRY;

 	return bytes;
 }

 /**
  * zfcp_qdio_send - set PCI flag in first SBALE and send req to QDIO
  * @qdio: pointer to struct zfcp_qdio
  * @q_req: pointer to struct zfcp_queue_req
  * Returns: 0 on success, error otherwise
  */
 int zfcp_qdio_send(struct zfcp_qdio *qdio, struct zfcp_queue_req *q_req)
 {
 	struct zfcp_qdio_queue *req_q = &qdio->req_q;
 	int first = q_req->sbal_first;
 	int count = q_req->sbal_number;
 	int retval;
 	unsigned int qdio_flags = QDIO_FLAG_SYNC_OUTPUT;

 	zfcp_qdio_account(qdio);

 	retval = do_QDIO(qdio->adapter->ccw_device, qdio_flags, 0, first,
 			 count);
 	if (unlikely(retval)) {
 		zfcp_qdio_zero_sbals(req_q->sbal, first, count);
 		return retval;
 	}

 	/* account for transferred buffers */
 	atomic_sub(count, &req_q->count);
 	req_q->first += count;
 	req_q->first %= QDIO_MAX_BUFFERS_PER_Q;
 	return 0;
 }


 static void zfcp_qdio_setup_init_data(struct qdio_initialize *id,
 				      struct zfcp_qdio *qdio)
 {

 	id->cdev = qdio->adapter->ccw_device;
 	id->q_format = QDIO_ZFCP_QFMT;
 	memcpy(id->adapter_name, dev_name(&id->cdev->dev), 8);
 	ASCEBC(id->adapter_name, 8);
 	id->qib_param_field_format = 0;
 	id->qib_param_field = NULL;
 	id->input_slib_elements = NULL;
 	id->output_slib_elements = NULL;
 	id->no_input_qs = 1;
 	id->no_output_qs = 1;
 	id->input_handler = zfcp_qdio_int_resp;
 	id->output_handler = zfcp_qdio_int_req;
 	id->int_parm = (unsigned long) qdio;
 	id->flags = QDIO_INBOUND_0COPY_SBALS |
 		    QDIO_OUTBOUND_0COPY_SBALS | QDIO_USE_OUTBOUND_PCIS;
 	id->input_sbal_addr_array = (void **) (qdio->resp_q.sbal);
 	id->output_sbal_addr_array = (void **) (qdio->req_q.sbal);

 }
 /**
  * zfcp_qdio_allocate - allocate queue memory and initialize QDIO data
  * @adapter: pointer to struct zfcp_adapter
  * Returns: -ENOMEM on memory allocation error or return value from
  *          qdio_allocate
  */
 int zfcp_qdio_allocate(struct zfcp_qdio *qdio, struct ccw_device *ccw_dev)
 {
 	struct qdio_initialize init_data;

 	if (zfcp_qdio_buffers_enqueue(qdio->req_q.sbal) ||
 	    zfcp_qdio_buffers_enqueue(qdio->resp_q.sbal))
 		return -ENOMEM;

 	zfcp_qdio_setup_init_data(&init_data, qdio);

 	return qdio_allocate(&init_data);
 }

 /**
  * zfcp_close_qdio - close qdio queues for an adapter
  * @qdio: pointer to structure zfcp_qdio
  */
 void zfcp_qdio_close(struct zfcp_qdio *qdio)
 {
 	struct zfcp_qdio_queue *req_q;
 	int first, count;

 	if (!(atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
 		return;

 	/* clear QDIOUP flag, thus do_QDIO is not called during qdio_shutdown */
 	req_q = &qdio->req_q;
 	spin_lock_bh(&qdio->req_q_lock);
 	atomic_clear_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &qdio->adapter->status);
 	spin_unlock_bh(&qdio->req_q_lock);

 	qdio_shutdown(qdio->adapter->ccw_device,
 		      QDIO_FLAG_CLEANUP_USING_CLEAR);

 	/* cleanup used outbound sbals */
 	count = atomic_read(&req_q->count);
 	if (count < QDIO_MAX_BUFFERS_PER_Q) {
 		first = (req_q->first + count) % QDIO_MAX_BUFFERS_PER_Q;
 		count = QDIO_MAX_BUFFERS_PER_Q - count;
 		zfcp_qdio_zero_sbals(req_q->sbal, first, count);
 	}
 	req_q->first = 0;
 	atomic_set(&req_q->count, 0);
 	qdio->resp_q.first = 0;
 	atomic_set(&qdio->resp_q.count, 0);
 }

 /**
  * zfcp_qdio_open - prepare and initialize response queue
  * @qdio: pointer to struct zfcp_qdio
  * Returns: 0 on success, otherwise -EIO
  */
 int zfcp_qdio_open(struct zfcp_qdio *qdio)
 {
 	struct qdio_buffer_element *sbale;
 	struct qdio_initialize init_data;
 	struct ccw_device *cdev = qdio->adapter->ccw_device;
 	int cc;

 	if (atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP)
 		return -EIO;

 	zfcp_qdio_setup_init_data(&init_data, qdio);

 	if (qdio_establish(&init_data))
 		goto failed_establish;

 	if (qdio_activate(cdev))
 		goto failed_qdio;

 	for (cc = 0; cc < QDIO_MAX_BUFFERS_PER_Q; cc++) {
 		sbale = &(qdio->resp_q.sbal[cc]->element[0]);
 		sbale->length = 0;
 		sbale->flags = SBAL_FLAGS_LAST_ENTRY;
 		sbale->addr = NULL;
 	}

 	if (do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, 0,
 		     QDIO_MAX_BUFFERS_PER_Q))
 		goto failed_qdio;

 	/* set index of first avalable SBALS / number of available SBALS */
 	qdio->req_q.first = 0;
 	atomic_set(&qdio->req_q.count, QDIO_MAX_BUFFERS_PER_Q);

 	return 0;

 failed_qdio:
 	qdio_shutdown(cdev, QDIO_FLAG_CLEANUP_USING_CLEAR);
 failed_establish:
 	dev_err(&cdev->dev,
 		"Setting up the QDIO connection to the FCP adapter failed\n");
 	return -EIO;
 }
	/*
	* zfcp device driver
	*
	* Setup and helper functions to access QDIO.
	*
	* Copyright IBM Corporation 2002, 2009
	*/

	#define KMSG_COMPONENT "zfcp"
	#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

	#include "zfcp_ext.h"

	#define QBUFF_PER_PAGE (PAGE_SIZE / sizeof(struct qdio_buffer))

	static int zfcp_qdio_buffers_enqueue(struct qdio_buffer **sbal)
	{
	int pos;

	for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos += QBUFF_PER_PAGE) {
	sbal[pos] = (struct qdio_buffer *) get_zeroed_page(GFP_KERNEL);
	if (!sbal[pos])
	return -ENOMEM;
	}
	for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos++)
	if (pos % QBUFF_PER_PAGE)
	sbal[pos] = sbal[pos - 1] + 1;
	return 0;
	}

	static struct qdio_buffer_element *
	zfcp_qdio_sbale(struct zfcp_qdio_queue *q, int sbal_idx, int sbale_idx)
	{
	return &q->sbal[sbal_idx]->element[sbale_idx];
	}

	/**
	* zfcp_qdio_free - free memory used by request- and resposne queue
	* @qdio: pointer to the zfcp_qdio structure
	*/
	void zfcp_qdio_free(struct zfcp_qdio *qdio)
	{
	struct qdio_buffer sbal_req, sbal_resp;
	int p;

	if (qdio->adapter->ccw_device)
	qdio_free(qdio->adapter->ccw_device);

	sbal_req = qdio->req_q.sbal;
	sbal_resp = qdio->resp_q.sbal;

	for (p = 0; p < QDIO_MAX_BUFFERS_PER_Q; p += QBUFF_PER_PAGE) {
	free_page((unsigned long) sbal_req[p]);
	free_page((unsigned long) sbal_resp[p]);
	}
	}

	static void zfcp_qdio_handler_error(struct zfcp_qdio qdio, char id)
	{
	struct zfcp_adapter *adapter = qdio->adapter;

	dev_warn(&adapter->ccw_device->dev, "A QDIO problem occurred\n");

	zfcp_erp_adapter_reopen(adapter,
	ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED \|
	ZFCP_STATUS_COMMON_ERP_FAILED, id, NULL);
	}

	static void zfcp_qdio_zero_sbals(struct qdio_buffer *sbal[], int first, int cnt)
	{
	int i, sbal_idx;

	for (i = first; i < first + cnt; i++) {
	sbal_idx = i % QDIO_MAX_BUFFERS_PER_Q;
	memset(sbal[sbal_idx], 0, sizeof(struct qdio_buffer));
	}
	}

	/* this needs to be called prior to updating the queue fill level */
	static void zfcp_qdio_account(struct zfcp_qdio *qdio)
	{
	ktime_t now;
	s64 span;
	int free, used;

	spin_lock(&qdio->stat_lock);
	now = ktime_get();
	span = ktime_us_delta(now, qdio->req_q_time);
	free = max(0, atomic_read(&qdio->req_q.count));
	used = QDIO_MAX_BUFFERS_PER_Q - free;
	qdio->req_q_util += used * span;
	qdio->req_q_time = now;
	spin_unlock(&qdio->stat_lock);
	}

	static void zfcp_qdio_int_req(struct ccw_device *cdev, unsigned int qdio_err,
	int queue_no, int first, int count,
	unsigned long parm)
	{
	struct zfcp_qdio qdio = (struct zfcp_qdio ) parm;
	struct zfcp_qdio_queue *queue = &qdio->req_q;

	if (unlikely(qdio_err)) {
	zfcp_dbf_hba_qdio(qdio->adapter->dbf, qdio_err, first,
	count);
	zfcp_qdio_handler_error(qdio, "qdireq1");
	return;
	}

	/* cleanup all SBALs being program-owned now */
	zfcp_qdio_zero_sbals(queue->sbal, first, count);

	zfcp_qdio_account(qdio);
	atomic_add(count, &queue->count);
	wake_up(&qdio->req_q_wq);
	}

	static void zfcp_qdio_resp_put_back(struct zfcp_qdio *qdio, int processed)
	{
	struct zfcp_qdio_queue *queue = &qdio->resp_q;
	struct ccw_device *cdev = qdio->adapter->ccw_device;
	u8 count, start = queue->first;
	unsigned int retval;

	count = atomic_read(&queue->count) + processed;

	retval = do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, start, count);

	if (unlikely(retval)) {
	atomic_set(&queue->count, count);
	/* FIXME: Recover this with an adapter reopen? */
	} else {
	queue->first += count;
	queue->first %= QDIO_MAX_BUFFERS_PER_Q;
	atomic_set(&queue->count, 0);
	}
	}

	static void zfcp_qdio_int_resp(struct ccw_device *cdev, unsigned int qdio_err,
	int queue_no, int first, int count,
	unsigned long parm)
	{
	struct zfcp_qdio qdio = (struct zfcp_qdio ) parm;
	int sbal_idx, sbal_no;

	if (unlikely(qdio_err)) {
	zfcp_dbf_hba_qdio(qdio->adapter->dbf, qdio_err, first,
	count);
	zfcp_qdio_handler_error(qdio, "qdires1");
	return;
	}

	/*
	* go through all SBALs from input queue currently
	* returned by QDIO layer
	*/
	for (sbal_no = 0; sbal_no < count; sbal_no++) {
	sbal_idx = (first + sbal_no) % QDIO_MAX_BUFFERS_PER_Q;
	/* go through all SBALEs of SBAL */
	zfcp_fsf_reqid_check(qdio, sbal_idx);
	}

	/*
	* put range of SBALs back to response queue
	* (including SBALs which have already been free before)
	*/
	zfcp_qdio_resp_put_back(qdio, count);
	}

	/**
	* zfcp_qdio_sbale_req - return ptr to SBALE of req_q for a struct zfcp_fsf_req
	* @qdio: pointer to struct zfcp_qdio
	* @q_rec: pointer to struct zfcp_queue_rec
	* Returns: pointer to qdio_buffer_element (SBALE) structure
	*/
	struct qdio_buffer_element zfcp_qdio_sbale_req(struct zfcp_qdio qdio,
	struct zfcp_queue_req *q_req)
	{
	return zfcp_qdio_sbale(&qdio->req_q, q_req->sbal_last, 0);
	}

	/**
	* zfcp_qdio_sbale_curr - return curr SBALE on req_q for a struct zfcp_fsf_req
	* @fsf_req: pointer to struct fsf_req
	* Returns: pointer to qdio_buffer_element (SBALE) structure
	*/
	struct qdio_buffer_element zfcp_qdio_sbale_curr(struct zfcp_qdio qdio,
	struct zfcp_queue_req *q_req)
	{
	return zfcp_qdio_sbale(&qdio->req_q, q_req->sbal_last,
	q_req->sbale_curr);
	}

	static void zfcp_qdio_sbal_limit(struct zfcp_qdio *qdio,
	struct zfcp_queue_req *q_req, int max_sbals)
	{
	int count = atomic_read(&qdio->req_q.count);
	count = min(count, max_sbals);
	q_req->sbal_limit = (q_req->sbal_first + count - 1)
	% QDIO_MAX_BUFFERS_PER_Q;
	}

	static struct qdio_buffer_element *
	zfcp_qdio_sbal_chain(struct zfcp_qdio qdio, struct zfcp_queue_req q_req,
	unsigned long sbtype)
	{
	struct qdio_buffer_element *sbale;

	/* set last entry flag in current SBALE of current SBAL */
	sbale = zfcp_qdio_sbale_curr(qdio, q_req);
	sbale->flags \|= SBAL_FLAGS_LAST_ENTRY;

	/* don't exceed last allowed SBAL */
	if (q_req->sbal_last == q_req->sbal_limit)
	return NULL;

	/* set chaining flag in first SBALE of current SBAL */
	sbale = zfcp_qdio_sbale_req(qdio, q_req);
	sbale->flags \|= SBAL_FLAGS0_MORE_SBALS;

	/* calculate index of next SBAL */
	q_req->sbal_last++;
	q_req->sbal_last %= QDIO_MAX_BUFFERS_PER_Q;

	/* keep this requests number of SBALs up-to-date */
	q_req->sbal_number++;

	/* start at first SBALE of new SBAL */
	q_req->sbale_curr = 0;

	/* set storage-block type for new SBAL */
	sbale = zfcp_qdio_sbale_curr(qdio, q_req);
	sbale->flags \|= sbtype;

	return sbale;
	}

	static struct qdio_buffer_element *
	zfcp_qdio_sbale_next(struct zfcp_qdio qdio, struct zfcp_queue_req q_req,
	unsigned int sbtype)
	{
	if (q_req->sbale_curr == ZFCP_LAST_SBALE_PER_SBAL)
	return zfcp_qdio_sbal_chain(qdio, q_req, sbtype);
	q_req->sbale_curr++;
	return zfcp_qdio_sbale_curr(qdio, q_req);
	}

	static void zfcp_qdio_undo_sbals(struct zfcp_qdio *qdio,
	struct zfcp_queue_req *q_req)
	{
	struct qdio_buffer **sbal = qdio->req_q.sbal;
	int first = q_req->sbal_first;
	int last = q_req->sbal_last;
	int count = (last - first + QDIO_MAX_BUFFERS_PER_Q) %
	QDIO_MAX_BUFFERS_PER_Q + 1;
	zfcp_qdio_zero_sbals(sbal, first, count);
	}

	static int zfcp_qdio_fill_sbals(struct zfcp_qdio *qdio,
	struct zfcp_queue_req *q_req,
	unsigned int sbtype, void *start_addr,
	unsigned int total_length)
	{
	struct qdio_buffer_element *sbale;
	unsigned long remaining, length;
	void *addr;

	/* split segment up */
	for (addr = start_addr, remaining = total_length; remaining > 0;
	addr += length, remaining -= length) {
	sbale = zfcp_qdio_sbale_next(qdio, q_req, sbtype);
	if (!sbale) {
	atomic_inc(&qdio->req_q_full);
	zfcp_qdio_undo_sbals(qdio, q_req);
	return -EINVAL;
	}

	/* new piece must not exceed next page boundary */
	length = min(remaining,
	(PAGE_SIZE - ((unsigned long)addr &
	(PAGE_SIZE - 1))));
	sbale->addr = addr;
	sbale->length = length;
	}
	return 0;
	}

	/**
	* zfcp_qdio_sbals_from_sg - fill SBALs from scatter-gather list
	* @fsf_req: request to be processed
	* @sbtype: SBALE flags
	* @sg: scatter-gather list
	* @max_sbals: upper bound for number of SBALs to be used
	* Returns: number of bytes, or error (negativ)
	*/
	int zfcp_qdio_sbals_from_sg(struct zfcp_qdio *qdio,
	struct zfcp_queue_req *q_req,
	unsigned long sbtype, struct scatterlist *sg,
	int max_sbals)
	{
	struct qdio_buffer_element *sbale;
	int retval, bytes = 0;

	/* figure out last allowed SBAL */
	zfcp_qdio_sbal_limit(qdio, q_req, max_sbals);

	/* set storage-block type for this request */
	sbale = zfcp_qdio_sbale_req(qdio, q_req);
	sbale->flags \|= sbtype;

	for (; sg; sg = sg_next(sg)) {
	retval = zfcp_qdio_fill_sbals(qdio, q_req, sbtype,
	sg_virt(sg), sg->length);
	if (retval < 0)
	return retval;
	bytes += sg->length;
	}

	/* assume that no other SBALEs are to follow in the same SBAL */
	sbale = zfcp_qdio_sbale_curr(qdio, q_req);
	sbale->flags \|= SBAL_FLAGS_LAST_ENTRY;

	return bytes;
	}

	/**
	* zfcp_qdio_send - set PCI flag in first SBALE and send req to QDIO
	* @qdio: pointer to struct zfcp_qdio
	* @q_req: pointer to struct zfcp_queue_req
	* Returns: 0 on success, error otherwise
	*/
	int zfcp_qdio_send(struct zfcp_qdio qdio, struct zfcp_queue_req q_req)
	{
	struct zfcp_qdio_queue *req_q = &qdio->req_q;
	int first = q_req->sbal_first;
	int count = q_req->sbal_number;
	int retval;
	unsigned int qdio_flags = QDIO_FLAG_SYNC_OUTPUT;

	zfcp_qdio_account(qdio);

	retval = do_QDIO(qdio->adapter->ccw_device, qdio_flags, 0, first,
	count);
	if (unlikely(retval)) {
	zfcp_qdio_zero_sbals(req_q->sbal, first, count);
	return retval;
	}

	/* account for transferred buffers */
	atomic_sub(count, &req_q->count);
	req_q->first += count;
	req_q->first %= QDIO_MAX_BUFFERS_PER_Q;
	return 0;
	}


	static void zfcp_qdio_setup_init_data(struct qdio_initialize *id,
	struct zfcp_qdio *qdio)
	{

	id->cdev = qdio->adapter->ccw_device;
	id->q_format = QDIO_ZFCP_QFMT;
	memcpy(id->adapter_name, dev_name(&id->cdev->dev), 8);
	ASCEBC(id->adapter_name, 8);
	id->qib_param_field_format = 0;
	id->qib_param_field = NULL;
	id->input_slib_elements = NULL;
	id->output_slib_elements = NULL;
	id->no_input_qs = 1;
	id->no_output_qs = 1;
	id->input_handler = zfcp_qdio_int_resp;
	id->output_handler = zfcp_qdio_int_req;
	id->int_parm = (unsigned long) qdio;
	id->flags = QDIO_INBOUND_0COPY_SBALS \|
	QDIO_OUTBOUND_0COPY_SBALS \| QDIO_USE_OUTBOUND_PCIS;
	id->input_sbal_addr_array = (void **) (qdio->resp_q.sbal);
	id->output_sbal_addr_array = (void **) (qdio->req_q.sbal);

	}
	/**
	* zfcp_qdio_allocate - allocate queue memory and initialize QDIO data
	* @adapter: pointer to struct zfcp_adapter
	* Returns: -ENOMEM on memory allocation error or return value from
	* qdio_allocate
	*/
	int zfcp_qdio_allocate(struct zfcp_qdio qdio, struct ccw_device ccw_dev)
	{
	struct qdio_initialize init_data;

	if (zfcp_qdio_buffers_enqueue(qdio->req_q.sbal) \|\|
	zfcp_qdio_buffers_enqueue(qdio->resp_q.sbal))
	return -ENOMEM;

	zfcp_qdio_setup_init_data(&init_data, qdio);

	return qdio_allocate(&init_data);
	}

	/**
	* zfcp_close_qdio - close qdio queues for an adapter
	* @qdio: pointer to structure zfcp_qdio
	*/
	void zfcp_qdio_close(struct zfcp_qdio *qdio)
	{
	struct zfcp_qdio_queue *req_q;
	int first, count;

	if (!(atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
	return;

	/* clear QDIOUP flag, thus do_QDIO is not called during qdio_shutdown */
	req_q = &qdio->req_q;
	spin_lock_bh(&qdio->req_q_lock);
	atomic_clear_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &qdio->adapter->status);
	spin_unlock_bh(&qdio->req_q_lock);

	qdio_shutdown(qdio->adapter->ccw_device,
	QDIO_FLAG_CLEANUP_USING_CLEAR);

	/* cleanup used outbound sbals */
	count = atomic_read(&req_q->count);
	if (count < QDIO_MAX_BUFFERS_PER_Q) {
	first = (req_q->first + count) % QDIO_MAX_BUFFERS_PER_Q;
	count = QDIO_MAX_BUFFERS_PER_Q - count;
	zfcp_qdio_zero_sbals(req_q->sbal, first, count);
	}
	req_q->first = 0;
	atomic_set(&req_q->count, 0);
	qdio->resp_q.first = 0;
	atomic_set(&qdio->resp_q.count, 0);
	}

	/**
	* zfcp_qdio_open - prepare and initialize response queue
	* @qdio: pointer to struct zfcp_qdio
	* Returns: 0 on success, otherwise -EIO
	*/
	int zfcp_qdio_open(struct zfcp_qdio *qdio)
	{
	struct qdio_buffer_element *sbale;
	struct qdio_initialize init_data;
	struct ccw_device *cdev = qdio->adapter->ccw_device;
	int cc;

	if (atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP)
	return -EIO;

	zfcp_qdio_setup_init_data(&init_data, qdio);

	if (qdio_establish(&init_data))
	goto failed_establish;

	if (qdio_activate(cdev))
	goto failed_qdio;

	for (cc = 0; cc < QDIO_MAX_BUFFERS_PER_Q; cc++) {
	sbale = &(qdio->resp_q.sbal[cc]->element[0]);
	sbale->length = 0;
	sbale->flags = SBAL_FLAGS_LAST_ENTRY;
	sbale->addr = NULL;
	}

	if (do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, 0,
	QDIO_MAX_BUFFERS_PER_Q))
	goto failed_qdio;

	/* set index of first avalable SBALS / number of available SBALS */
	qdio->req_q.first = 0;
	atomic_set(&qdio->req_q.count, QDIO_MAX_BUFFERS_PER_Q);

	return 0;

	failed_qdio:
	qdio_shutdown(cdev, QDIO_FLAG_CLEANUP_USING_CLEAR);
	failed_establish:
	dev_err(&cdev->dev,
	"Setting up the QDIO connection to the FCP adapter failed\n");
	return -EIO;
	}